Dilazep: an inhibitor of adenosine uptake with intrinsic calcium antagonistic properties

Abstract

Concentrations of dilazep which were ineffective in altering the muscular tone of the guinea‐pig taenia caeci (0·03, 0·3 μM) or the phasic mechanical activity of the rabbit proximal ileum (0·03 μM) markedly potentiated the inhibitory action of adenosine on both these parameters. Dilazep, 0·3 μM or greater, dose‐dependently inhibited the mechanical activity of the proximal ileum. This inhibitory action was probably mediated by more than one mechanism, as shown by the fact that theophylline (50,100 μM) antagonized the effect at lower dilazep concentrations (up to 3 μM) leaving essentially unchanged the response to higher concentrations (6, 10 μM). Similarly, the responses to low doses of dilaz..